The working papers published in the Series constitute work in progress circulated to stimulate discussion and critical comments. Views expressed represent exclusively the authors' own opinions and do not necessarily reflect those of the editor.

This paper analyzes the effect of learning-by-doing in R&D on firms' incentives to innovate. As a benchmark without learning it is shown that relaxing the usual assumption of imposed imitation yields additional strategic effects. Therefore, the leader's R&D effort increases with the gap as she is trying to avoid competition in the future. When firms gain experience by performing R&D technological leaders rest on their laurels allowing followers to catch up. Contrary to the benchmark case, the leader's innovation effort declines with the lead. This causes an equilibrium where the incentives to innovate are highest when competition is most intense.

While liberalization in energy markets has been a widely successful process all over the world, incumbents often still hold a dominant position. Thus, electricity wholesale markets are subject to market surveillance. Nevertheless, consolidated findings on abusive practices of market power and their cause and effect in wholesale electricity markets are scarce and non-controversial market monitoring practices fail to exist. Our application of the established measure of market concentration RSI shows that it serves as a decent indicator for the rents that can be gained in the market but also reveals considerable weaknesses of the RSI. Therefore, we propose and apply the "Return on Withholding Capacity Index" (RWC) representing a measure of the firms' incentive of withholding capacity as a complementary index to the RSI.

(2007) to endogenous prices and strategic oligopoly competition. We show that the optimal decision rule is an (S, s) order policy and prices and inventory are strategic substitutes. Fixed ordering costs generate infrequent orders. Consequently, with strategic competition in prices, (S, s) inventory behavior together with demand uncertainty generates endogenous cyclical patterns in prices without any exogenous shocks. Hence, the developed model provides a promising framework for explaining dynamics of commodity markets and especially observed autocorrelation in price fluctuations.